Recently, research on beamforming technology has been conducted intensively as an important technique for improving signal quality by reducing loss in propagation paths and acquiring high signal to interference and noise ratio (SINR) in mobile communication systems.
In a mobile communication system (hereinafter, referred to as “a beamforming system”) using beamforming technology, transmit (Tx) beamforming or/and receive (Rx) beamforming are used. The Tx beamforming is generally a technique to focus a signal transmitted from each antenna in a specific direction using a plurality of antennas. The combination of the plurality of antennas is called an array antenna, and each of the antennas included in the array antenna is called an antenna element. The propagation distance of a signal is increased by using Tx beamforming, and since a signal is hardly received in directions other than a relevant direction, interference to other users is considerably reduced. The Rx beamforming is a technique to focus reception of radio waves in a specific direction by using a reception antenna array in a receiver. The signal sensitivity of a signal incoming in a relevant direction is increased by using Rx beamforming and signals incoming in directions other than the relevant direction are excluded from received signals, thereby blocking interference signals. In such a beamforming system, a signal is focused in a specific direction, and therefore, a transmission path of a beam is changed depending on in which direction a beam is transmitted. As a transmission path of a beam is changed, a difference in signal reception occurs in a receiver.
Therefore, there is a need to transmit and receive data in consideration of a difference in arrival time between signals which may be caused by different beam transmission paths.